C++

Read Text at a 64-bit Offset from a Remote SFTP File

Demonstrates the Chilkat SFtp.ReadFileText64 method, which reads up to a number of bytes from a specific 64-bit byte offset of an open handle and decodes them to text. The arguments are the handle, the offset, the maximum number of bytes, and the charset. The 64-bit offset supports very large files.

Background: This is the large-file counterpart to reading at a 32-bit offset: use it whenever the position you need lies beyond the ~4 GB reach of a 32-bit integer, for example seeking into a multi-gigabyte archive or database file. Everything else about the read is the same.

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C++

#include <CkSFtp.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  Demonstrates the SFtp.ReadFileText64 method, which reads up to a number of bytes from a
    //  specific 64-bit byte offset of an open handle and decodes them to text.  The 1st argument is
    //  the handle, the 2nd is the offset, the 3rd is the maximum number of bytes, and the 4th is the
    //  charset.  The 64-bit offset supports very large files.

    CkSFtp sftp;

    //  Connect, authenticate, and initialize the SFTP subsystem.
    int port = 22;
    success = sftp.Connect("sftp.example.com",port);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    const char *password = "mySshPassword";

    success = sftp.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    success = sftp.InitializeSftp();
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    const char *handle = sftp.openFile("subdir/hugefile.dat","readOnly","openExisting");
    if (sftp.get_LastMethodSuccess() == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    //  Read 6 bytes starting at a byte offset beyond the 32-bit (4 GB) range.
    __int64 offset = 5000000000;
    int numBytes = 6;
    const char *text = sftp.readFileText64(handle,offset,numBytes,"utf-8");
    if (sftp.get_LastMethodSuccess() == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    std::cout << text << "\r\n";

    success = sftp.CloseHandle(handle);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    sftp.Disconnect();
    }